Breast Cancer
Breast cancer, also referred to as mammary tumor cancer, is the second most common cancer among women, accounting for a third of the cancers diagnosed in the United States. One in nine women will develop breast cancer in her lifetime and about 192,000 new cases of breast cancer are diagnosed annually with about 42,000 deaths. Bevers, Primary Prevention of Breast Cancer, in Breast Cancer, 20-54 (Kelly K Hunt et al., ed., 2001); Kochanek et al., 49 Nat'l. Vital Statistics Reports 1, 14 (2001). Breast cancer is extremely rare in women younger than 20 and is very rare in women under 30. The incidence of breast cancer rises with age and becomes significant by age 50. White Non-Hispanic women have the highest incidence rate for breast cancer and Korean women have the lowest. Increased prevalence of the genetic mutations BRCA1 and BRCA2 that promote breast and other cancers are found in Ashkenazi Jews. African American women have the highest mortality rate for breast cancer among these same groups (31 per 100,000), while Chinese women have the lowest at 11 per 100,000. Although men can get breast cancer, this is extremely rare. In the United States it is estimated there will be 217,440 new cases of breast cancer and 40,580 deaths due to breast cancer in 2004. (American Cancer Society Website: cancer with the extension .org of the world wide web). With the exception of those cases with associated genetic factors, precise causes of breast cancer are not known.
In the treatment of breast cancer, there is considerable emphasis on detection and risk assessment because early and accurate staging of breast cancer has a significant impact on survival. For example, breast cancer detected at an early stage (stage T0, discussed below) has a five-year survival rate of 92%. Conversely, if the cancer is not detected until a late stage (i.e., stage T4 (IV)), the five-year survival rate is reduced to 13%. AJCC Cancer Staging Handbook pp. 164-65 (Irvin D. Fleming et al. eds., 5th ed. 1998). Some detection techniques, such as mammography and biopsy, involve increased discomfort, expense, and/or radiation, and are only prescribed only to patients with an increased risk of breast cancer.
Current methods for predicting or detecting breast cancer risk are not optimal. One method for predicting the relative risk of breast cancer is by examining a patient's risk factors and pursuing aggressive diagnostic and treatment regiments for high risk patients. A patient's risk of breast cancer has been positively associated with increasing age, nulliparity, family history of breast cancer, personal history of breast cancer, early menarche, late menopause, late age of first full term pregnancy, prior proliferative breast disease, irradiation of the breast at an early age and a personal history of malignancy. Lifestyle factors such as fat consumption, alcohol consumption, education, and socioeconomic status have also been associated with an increased incidence of breast cancer although a direct cause and effect relationship has not been established. While these risk factors are statistically significant, their weak association with breast cancer limited their usefulness. Most women who develop breast cancer have none of the risk factors listed above, other than the risk that comes with growing older. NIH Publication No. 00-1556 (2000).
Current screening methods for detecting cancer, such as breast self-exam, ultrasound, and mammography have drawbacks that reduce their effectiveness or prevent their widespread adoption. Breast self-exams, while useful, are unreliable for the detection of breast cancer in the initial stages where the tumor is small and difficult to detect by palpation. Ultrasound measurements require skilled operators at an increased expense. Mammography, while sensitive, is subject to over diagnosis in the detection of lesions that have questionable malignant potential. There is also the fear of the radiation used in mammography because prior chest radiation is a factor associated with an increase incidence of breast cancer.
At this time, there are no adequate methods of breast cancer prevention. The current methods of breast cancer prevention involve prophylactic mastectomy (mastectomy performed before cancer diagnosis) and chemoprevention (chemotherapy before cancer diagnosis) which are drastic measures that limit their adoption even among women with increased risk of breast cancer. Bevers, supra.
A number of genetic markers have been associated with breast cancer. Examples of these markers include carcinoembryonic antigen (CEA) (Mughal et al., JAMA 249:1881 (1983)), MUC-1 (Frische and Liu, J. Clin. Ligand 22:320 (2000)), HER-2/neu (Haris et al., Proc. Am. Soc. Clin. Oncology 15:A96 (1996)), uPA, PAI-1, LPA, LPC, RAK and BRCA (Esteva and Fritsche, Serum and Tissue Markers for Breast Cancer, in Breast Cancer, 286-308 (2001)). These markers have problems with limited sensitivity, low correlation, and false negatives which limit their use for initial diagnosis. For example, while the BRCA1 gene mutation is useful as an indicator of an increased risk for breast cancer, it has limited use in cancer diagnosis because only 6.2% of breast cancers are BRCA1 positive. Malone et al., JAMA 279:922 (1998). See also, Mewman et al., JAMA 279:915 (1998) (correlation of only 3.3%).
There are four primary classifications of breast cancer varying by the site of origin and the extent of disease development.                I. Ductal carcinoma in situ (DCIS): Malignant transformation of ductal epithelial cells that remain in their normal position. DCIS is a purely localized disease, incapable of metastasis.        II. Invasive ductal carcinoma (IDC): Malignancy of the ductal epithelial cells breaking through the basal membrane and into the supporting tissue of the breast. IDC may eventually spread elsewhere in the body.        III. Lobular carcinoma in situ (LCIS): Malignancy arising in a single lobule of the breast that fails to extend through the lobule wall, it generally remains localized.        IV. Infiltrating lobular carcinoma (ILC): Malignancy arising in a single lobule of the breast and invading directly through the lobule wall into adjacent tissues. By virtue of its invasion beyond the lobule wall, ILC may penetrate lymphatics and blood vessels and spread to distant sites.        
For purpose of determining prognosis and treatment, these four breast cancer types have been staged according to the size of the primary tumor (T), the involvement of lymph nodes (N), and the presence of metastasis (M). Although DCIS by definition represents localized stage I disease, the other forms of breast cancer may range from stage II to stage IV. There are additional prognostic factors that further serve to guide surgical and medical intervention. The most common ones are total number of lymph nodes involved, ER (estrogen receptor) status, Her2/neu receptor status and histologic grades.
Breast cancers are diagnosed into the appropriate stage categories recognizing that different treatments are more effective for different stages of cancer. Stage TX indicates that primary tumor cannot be assessed (i.e., tumor was removed or breast tissue was removed). Stage T0 is characterized by abnormalities such as hyperplasia but with no evidence of primary tumor. Stage Tis is characterized by carcinoma in situ, intraductal carcinoma, lobular carcinoma in situ, or Paget's disease of the nipple with no tumor. Stage T1 (I) is characterized as having a tumor of 2 cm or less in the greatest dimension. Within stage T1, Tmic indicates microinvasion of 0.1 cm or less, T1a indicates a tumor of between 0.1 to 0.5 cm, T1b indicates a tumor of between 0.5 to 1 cm, and T1c indicates tumors of between 1 cm to 2 cm. Stage T2 (II) is characterized by tumors from 2 cm to 5 cm in the greatest dimension. Tumors greater than 5 cm in size are classified as stage T3 (III). Stage T4 (IV) indicates a tumor of any size with extension to the chest wall or skin. Within stage T4, T4a indicates extension of the tumor to the chess wall, T4b indicates edema or ulceration of the skin of the breast or satellite skin nodules confined to the same breast, T4c indicates a combination of T4a and T4b, and T4d indicates inflammatory carcinoma. AJCC Cancer Staging Handbook pp. 159-70 (Irvin D. Fleming et al. eds., 5th ed. 1998). In addition to standard staging, breast tumors may be classified according to their estrogen receptor and progesterone receptor protein status. Fisher et al., Breast Cancer Research and Treatment 7:147 (1986). Additional pathological status, such as HER2/neu status may also be useful. Thor et al., J. Nat'l. Cancer Inst. 90:1346 (1998); Paik et al., J. Nat'l. Cancer Inst. 90:1361 (1998); Hutchins et al., Proc. Am. Soc. Clin. Oncology 17:A2 (1998); and Simpson et al., J. Clin. Oncology 18:2059 (2000).
In addition to the staging of the primary tumor, breast cancer metastases to regional lymph nodes may be staged. Stage NX indicates that the lymph nodes cannot be assessed (e.g., previously removed). Stage N0 indicates no regional lymph node metastasis. Stage N1 indicates metastasis to movable ipsilateral axillary lymph nodes. Stage N2 indicates metastasis to ipsilateral axillary lymph nodes fixed to one another or to other structures. Stage N3 indicates metastasis to ipsilateral internal mammary lymph nodes. Id.
Stage determination has potential prognostic value and provides criteria for designing optimal therapy. Simpson et al., J. Clin. Oncology 18:2059 (2000). Generally, pathological staging of breast cancer is preferable to clinical staging because the former gives a more accurate prognosis. However, clinical staging would be preferred if it were as accurate as pathological staging because it does not depend on an invasive procedure to obtain tissue for pathological evaluation. Staging of breast cancer would be improved by detecting new markers in cells, tissues, or bodily fluids which could differentiate between different stages of invasion. Progress in this field will allow more rapid and reliable method for treating breast cancer patients.
Treatment of breast cancer is generally decided after an accurate staging of the primary tumor. Primary treatment options include breast conserving therapy (lumpectomy, breast irradiation, and surgical staging of the axilla), and modified radical mastectomy. Additional treatments include chemotherapy, regional irradiation, and, in extreme cases, terminating estrogen production by ovarian ablation.
Until recently, the customary treatment for all breast cancer was mastectomy. Fonseca et al., Annals of Internal Medicine 127:1013 (1997). However, recent data indicate that less radical procedures may be equally effective, in terms of survival, for early stage breast cancer. Fisher et al., J. of Clinical Oncology 16:441 (1998). The treatment options for a patient with early stage breast cancer (i.e., stage Tis) may be breast-sparing surgery followed by localized radiation therapy at the breast. Alternatively, mastectomy optionally coupled with radiation or breast reconstruction may be employed. These treatment methods are equally effective in the early stages of breast cancer.
Patients with stage I and stage II breast cancer requires surgery with chemotherapy and/or hormonal therapy. Surgery is of limited use in Stage III and stage IV patients. Thus, these patients are better candidates for chemotherapy and radiation therapy with surgery limited to biopsy to permit initial staging or subsequent restaging because cancer is rarely curative at this stage of the disease. AJCC Cancer Staging Handbook 84, 164-65 (Irvin D. Fleming et al. eds., 5th ed. 1998).
In an effort to provide more treatment options to patients, efforts are underway to define an earlier stage of breast cancer with low recurrence which could be treated with lumpectomy without postoperative radiation treatment. While a number of attempts have been made to classify early stage breast cancer, no consensus recommendation on postoperative radiation treatment has been obtained from these studies. Page et al., Cancer 75:1219 (1995); Fisher et al., Cancer 75:1223 (1995); Silverstein et al., Cancer 77:2267 (1996).
Ovarian Cancer
Cancer of the ovaries is the fourth-most common cause of cancer death in women in the United States, with more than 23,000 new cases and roughly 14,000 deaths predicted for the year 2001. Shridhar, V. et al., Cancer Res. 61(15): 5895-904 (2001); Memarzadeh, S. & Berek, J. S., J. Reprod. Med. 46(7): 621-29 (2001). The American Cancer Society estimates that there will be about 25,580 new cases of ovarian cancer in 2004 in the United States alone. Ovarian cancer will cause about 16,090 deaths in the United States. ACS Website: cancer with the extension org of the world wide web. The incidence of ovarian cancer is of serious concern worldwide, with an estimated 191,000 new cases predicted annually. Runnebaum, I. B. & Stickeler, E., J. Cancer Res. Clin. Oncol. 127(2): 73-79 (2001). Unfortunately, women with ovarian cancer are typically asymptomatic until the disease has metastasized. Because effective screening for ovarian cancer is not available, roughly 70% of women diagnosed have an advanced stage of the cancer with a five-year survival rate of approximately 25-30%. Memarzadeh, S. & Berek, J. S., supra; Nunns, D. et al., Obstet. Gynecol. Surv. 55(12): 746-51. Conversely, women diagnosed with early stage ovarian cancer enjoy considerably higher survival rates. Werness, B. A. & Eltabbakh, G. H., Int'l. J. Gynecol. Pathol. 20(1): 48-63 (2001). Although our understanding of the etiology of ovarian cancer is incomplete, the results of extensive research in this area point to a combination of age, genetics, reproductive, and dietary/environmental factors. Age is a key risk factor in the development of ovarian cancer: while the risk for developing ovarian cancer before the age of 30 is slim, the incidence of ovarian cancer rises linearly between ages 30 to 50, increasing at a slower rate thereafter, with the highest incidence being among septagenarian women. Jeanne M. Schilder et al., Hereditary Ovarian Cancer. Clinical Syndromes and Management, in Ovarian Cancer 182 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001).
With respect to genetic factors, a family history of ovarian cancer is the most significant risk factor in the development of the disease, with that risk depending on the number of affected family members, the degree of their relationship to the woman, and which particular first degree relatives are affected by the disease. Id. Mutations in several genes have been associated with ovarian cancer, including BRCA1 and BRCA2, both of which play a key role in the development of breast cancer, as well as hMSH2 and hMLH1, both of which are associated with hereditary non-polyposis colon cancer. Katherine Y. Look, Epidemiology, Etiology, and Screening of Ovarian Cancer, in Ovarian Cancer 169, 171-73 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). BRCA1, located on chromosome 17, and BRCA2, located on chromosome 13, are tumor suppressor genes implicated in DNA repair; mutations in these genes are linked to roughly 10% of ovarian cancers. Id. at 171-72; Schilder et al., supra at 185-86. hMSH2 and hMLH1 are associated with DNA mismatch repair, and are located on chromosomes 2 and 3, respectively; it has been reported that roughly 3% of hereditary ovarian carcinomas are due to mutations in these genes. Look, supra at 173; Schilder et al., supra at 184, 188-89.
Reproductive factors have also been associated with an increased or reduced risk of ovarian cancer. Late menopause, nulliparity, and early age at menarche have all been linked with an elevated risk of ovarian cancer. Schilder et al., supra at 182. One theory hypothesizes that these factors increase the number of ovulatory cycles over the course of a woman's life, leading to “incessant ovulation,” which is thought to be the primary cause of mutations to the ovarian epithelium. Id.; Laura J. Havrilesky & Andrew Berchuck, Molecular Alterations in Sporadic Ovarian Cancer, in Ovarian Cancer 25 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). The mutations may be explained by the fact that ovulation results in the destruction and repair of that epithelium, necessitating increased cell division, thereby increasing the possibility that an undetected mutation will occur. Id. Support for this theory may be found in the fact that pregnancy, lactation, and the use of oral contraceptives, all of which suppress ovulation, confer a protective effect with respect to developing ovarian cancer. Id.
Among dietary/environmental factors, there would appear to be an association between high intake of animal fat or red meat and ovarian cancer, while the antioxidant Vitamin A, which prevents free radical formation and also assists in maintaining normal cellular differentiation, may offer a protective effect. Look, supra at 169. Reports have also associated asbestos and hydrous magnesium trisilicate (talc), the latter of which may be present in diaphragms and sanitary napkins. Id. at 169-70.
Current screening procedures for ovarian cancer, while of some utility, are quite limited in their diagnostic ability, a problem that is particularly acute at early stages of cancer progression when the disease is typically asymptomatic yet is most readily treated. Walter J. Burdette, Cancer: Etiology Diagnosis and Treatment 166 (1998); Memarzadeh & Berek, supra; Runnebaum & Stickeler, supra; Werness & Eltabbakh, supra. Commonly used screening tests include biannual rectovaginal pelvic examination, radioimmunoassay to detect the CA-125 serum tumor marker, and transvaginal ultrasonography. Burdette, supra at 166.
Pelvic examination has failed to yield adequate numbers of early diagnoses, and the other methods are not sufficiently accurate. Id. One study reported that only 15% of patients who suffered from ovarian cancer were diagnosed with the disease at the time of their pelvic examination. Look, supra at 174. Moreover, the CA-125 test is prone to giving false positives in pre-menopausal women and has been reported to be of low predictive value in post-menopausal women. Id. at 174-75. Although transvaginal ultrasonography is now the preferred procedure for screening for ovarian cancer, it is unable to distinguish reliably between benign and malignant tumors, and also cannot locate primary peritoneal malignancies or ovarian cancer if the ovary size is normal. Schilder et al., supra at 194-95. While genetic testing for mutations of the BRCA1, BRCA2, hMSH2, and hMLH1 genes is now available, these tests may be too costly for some patients and may also yield false negative or indeterminate results. Schilder et al., supra at 191-94.
Other markers of interest are HE4 and mesothelin. See Urban et al. Ovarian cancer screening Hematol Oncol Clin North Am. 2003 August; 17(4):989-1005; Hellstrom et al. The HE4 (WFDC2) protein is a biomarker for ovarian carcinoma, Cancer Res. 2003 Jul. 1; 63(13):3695-700; Ordonez, Application of mesothelin immunostaining in tumor diagnosis, Am J Surg Pathol. 2003 November; 27(11): 1418-28.
The staging of ovarian cancer, which is accomplished through surgical exploration, is crucial in determining the course of treatment and management of the disease. AJCC Cancer Staging Handbook 187 (Irvin D. Fleming et al. eds., 5th ed. 1998); Burdette, supra at 170; Memarzadeh & Berek, supra; Shridhar et al., supra. Staging is performed by reference to the classification system developed by the International Federation of Gynecology and Obstetrics. David H. Moore, Primary Surgical Management of Early Epithelial Ovarian Carcinoma, in Ovarian Cancer 203 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001); Fleming et al. eds., supra at 188. Stage I ovarian cancer is characterized by tumor growth that is limited to the ovaries and is comprised of three substages. Id. In substage IA, tumor growth is limited to one ovary, there is no tumor on the external surface of the ovary, the ovarian capsule is intact, and no malignant cells are present in ascites or peritoneal washings. Id. Substage IB is identical to IA, except that tumor growth is limited to both ovaries. Id. Substage IC refers to the presence of tumor growth limited to one or both ovaries, and also includes one or more of the following characteristics: capsule rupture, tumor growth on the surface of one or both ovaries, and malignant cells present in ascites or peritoneal washings. Id.
Stage II ovarian cancer refers to tumor growth involving one or both ovaries, along with pelvic extension. Id. Substage IIA involves extension and/or implants on the uterus and/or fallopian tubes, with no malignant cells in the ascites or peritoneal washings, while substage IIB involves extension into other pelvic organs and tissues, again with no malignant cells in the ascites or peritoneal washings. Id. Substage IIC involves pelvic extension as in IIA or IIB, but with malignant cells in the ascites or peritoneal washings. Id.
Stage III ovarian cancer involves tumor growth in one or both ovaries, with peritoneal metastasis beyond the pelvis confirmed by microscope and/or metastasis in the regional lymph nodes. Id. Substage IIIA is characterized by microscopic peritoneal metastasis outside the pelvis, with substage IIIB involving macroscopic peritoneal metastasis outside the pelvis 2 cm or less in greatest dimension. Id. Substage IIIC is identical to IIIB, except that the metastasis is greater than 2 cm in greatest dimension and may include regional lymph node metastasis. Id. Lastly, Stage IV refers to the presence distant metastasis, excluding peritoneal metastasis. Id.
While surgical staging is currently the benchmark for assessing the management and treatment of ovarian cancer, it suffers from considerable drawbacks, including the invasiveness of the procedure, the potential for complications, as well as the potential for inaccuracy. Moore, supra at 206-208, 213. In view of these limitations, attention has turned to developing alternative staging methodologies through understanding differential gene expression in various stages of ovarian cancer and by obtaining various biomarkers to help better assess the progression of the disease. Vartainen, J. et al., Int'l J. Cancer, 95(5): 313-16 (2001); Shridhar et al. supra; Baekelandt, M. et al., J. Clin. Oncol. 18(22): 3775-81.
The treatment of ovarian cancer typically involves a multiprong attack, with surgical intervention serving as the foundation of treatment. Dennis S. Chi & William J. Hoskins, Primary Surgical Management of Advanced Epithelial Ovarian Cancer, in Ovarian Cancer 241 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). For example, in the case of epithelial ovarian cancer, which accounts for approximately 90% of cases of ovarian cancer, treatment typically consists of: (1) cytoreductive surgery, including total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymphadenectomy, followed by (2) adjuvant chemotherapy with paclitaxel and either cisplatin or carboplatin. Eltabbakh, G. H. & Awtrey, C. S., Expert Op. Pharmacother. 2(10): 109-24. Despite a clinical response rate of 80% to the adjuvant therapy, most patients experience tumor recurrence within three years of treatment. Id. Certain patients may undergo a second cytoreductive surgery and/or second-line chemotherapy. Memarzadeh & Berek, supra.
From the foregoing, it is clear that procedures used for detecting, diagnosing, monitoring, staging, prognosticating, and preventing the recurrence of ovarian cancer are of critical importance to the outcome of the patient. Moreover, current procedures, while helpful in each of these analyses, are limited by their specificity, sensitivity, invasiveness, and/or their cost. As such, highly specific and sensitive procedures that would operate by way of detecting novel markers in cells, tissues, or bodily fluids, with minimal invasiveness and at a reasonable cost, would be highly desirable.
Accordingly, there is a great need for more sensitive and accurate methods for predicting whether a person is likely to develop ovarian cancer, for diagnosing ovarian cancer, for monitoring the progression of the disease, for staging the ovarian cancer, for determining whether the ovarian cancer has metastasized, and for imaging the ovarian cancer. There is also a need for better treatment of ovarian cancer.
Pancreatic Cancer
Pancreatic cancer is the thirteenth-most common cancer and eighth-most cause of cancer death worldwide. Donghui Li, Molecular Epidemiology, in Pancreatic Cancer 3 (Douglas B. Evans et al. eds., 2002). In the United States, cancer of the pancreas is the fourth-most common cancer in both males and females, accounting for five percent of cancer deaths and nearly 30,000 deaths overall. Id. The rates of pancreatic cancer are higher in men than women and higher in African-Americans as opposed to Caucasians. Id. at 9. The most significant predictor of pancreatic cancer is patient age; among Caucasians, the age-related incidence of pancreatic cancer increases continuously, even through the 85 and older category. Id. at 3. Approximately 80% of cases occur in the age range of 60 to 80, with those in their 80s experiencing a risk of acquiring the disease 40 times that of those in their 40s. Id. Furthermore, the American Cancer Society estimates that there will be about 31,800 new cases of pancreatic cancer in 2004 in the United States alone. Pancreatic cancer will cause about 31,200 deaths in the United States in the same year. ACS Website: cancer with the extension .org of the world wide web. Despite the efforts of researchers and physicians in devising treatments for pancreatic cancer, it remains almost universally fatal. James R. Howe, Molecular Markers as a Tool for the Early Diagnosis of Pancreatic Cancer, in Pancreatic Cancer 29 (Douglas B. Evans et al. eds., 2002).
Aside from age, a number of risk factors for pancreatic cancer have been identified, including smoking, diet, occupation, certain medical conditions, heredity, and molecular biologic. Smoking is the most important risk factor for acquiring the disease, with the link between smoking and pancreatic cancer being established in numerous studies. Li, supra at 3. The relative risk amounts to at least 1.5, increasing with the level of smoking to an outer risk ratio of 10-fold. Id. The next most important factor would appear to be diet, with increased risk associated with animal protein and fat intake, and decreased risk associated with intake of fruits and vegetables. Id. at 3-4. As for particular occupations, excessive rates of pancreatic cancer have been associated with workers in chemistry, coal and gas exploration, the metal industry, leather tanning, textiles, aluminum milling, and transportation. Id. at 4. A number of medical conditions have also been associated with an increased incidence of pancreatic cancer, including diabetes, chronic pancreatitis, gastrectomy, and cholecystectomy, although the cause and effect relationship between these conditions and pancreatic cancer has not been established. Id.
Hereditary genetic factors comprise less than 10% of the pancreatic cancer burden, with associations documented with hereditary pancreatitis, as well as germline mutations in familial cancer syndrome genes such as hMSH2 and hMLH1 (hereditary nonpolyposis colon cancer), p16 (familial atypical multiple mole-melanoma) and BRCA1/BRCA2 (breast and ovarian cancer). Id. at 3. While no other organ has a higher inherited basis for cancer than the pancreas, researchers have been unable to pinpoint the particular genetic defect(s) that contribute to one's susceptibility to pancreatic cancer. David H. Berger & William E. Fisher, Inherited Pancreatic Cancer Syndromes, in Pancreatic Cancer 73 (Douglas B. Evans et al. eds., 2002).
From the standpoint of molecular biology, research has revealed an association between pancreatic cancer and a number of genetic mutations, including the activation of the proto-oncogene K-ras and the inactivation of the tumor suppressor genes p53, p16, and DPC4. Marina E. Jean et al., The Molecular Biology of Pancreatic Cancer, in Pancreatic Cancer 15 (Douglas B. Evans et al. eds., 2002).
In one study of pancreatic adenocarcinomas, 83% possessed K-ras activation along with inactivation of p16 and p53. Id. K-ras mutations are found in 80 to 95% of pancreatic adenocarcinomas, with p53, p16, and DPC4 genes being the must frequently deleted tumor suppressor genes in cancer of the pancreas. Howe, supra at 29. Homozygous deletions, hypermethylation, and mutations of the p16 gene have been discovered in 85 to 98% of adenocarcinomas of the pancreas. Id. As might be expected by the role of alterations in the K-ras, p53, p16, and DPC4 genes, loss of regulation of the cell cycle would appear to be key to tumorigenesis in the pancreas, and may explain why this cancer is so aggressive. Jean, supra at 15. Research has also revealed a link between this cancer and abnormal regulation of certain growth factors and growth factor receptors, as well as an upregulation of matrix metalloproteinases and tumor angiogenesis regulators. Id. Epidermal growth factor, fibroblast growth factor, transforming growth factor-β, insulin-like growth factor, hepatocyte growth factor, and vascular endothelial growth factor may play various roles in pancreatic cancer, although such roles have not been elucidated. Id. at 18-22.
The development of screening techniques to detect the presence of pancreatic cancer is particularly essential for this deadly cancer, as most patients fail to present until their pancreatic tumors obstruct the bile duct or induce pain, at which point the tumors have invaded the capillary and lymphatic vessels that surround the pancreas, Howe, supra at 29; unfortunately, patients with the metastatic form of the disease typically survive less than one year after diagnosis, Jean et al., supra at 15. While computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) may assist in the diagnosis of symptomatic patients, there is presently no tool for screening for pancreatic tumors that would permit their early discovery, at which point they might be curable. Howe, supra at 29. Markers such as carcinoembryonic antigen, and antibodies generated against cell lines of human colonic cancer (CA 19-9 and CA 195), human ovarian cancer (CA 125), and human pancreatic cancer (SPAN-1 and DUPAN-2) may be elevated in the serum of patients with pancreatic cancer, but these markers are not sufficiently reliable to serve as screening tools due to their lack of specificity and appearance late in the disease. Walter J. Burdette, Cancer: Etiology, Diagnosis, and Treatment 99 (1998); Hasholzner, U. et al., Anticancer Res. 19(4A): 2477-80 (1999).
Due to the present lack of adequate screening methods, physicians are increasingly turning to techniques which employ methods of molecular biology as the most promising means for early diagnosis of the disease. Howe, supra at 30. At present, there is no high sensitivity, high specificity marker that enables the detection of pancreatic cancer in asymptomatic individuals, but several biological markers are under investigation. Id. Considerable efforts are currently focusing on K-ras, with researchers devising techniques to screen samples of pancreatic juice, bile, duodenal juice, or ERCP brushings to detect K-ras mutations. Id. Because the collection of these samples is invasive and not particularly helpful in screening those who are asymptomatic, researchers have also turned to serum and stool analysis for K-ras mutations, with the former being the most promising, as the latter is hindered by the complexity of the source material. Id. at 35-38, 42. Moreover, because serum levels of the transcription factor protein p53 may parallel cancer progression, p53 is likewise being studied as possible tumor marker. Id. at 37; Jean et al., supra at 17.
Once pancreatic cancer has been diagnosed, treatment decisions are made in reference to the stage of cancer progression. A number of imaging techniques are employed to stage pancreatic cancer, with computed tomography (CT) being the present method of choice, Harmeet Kaur et al., Pancreatic Cancer: Radiologic Staging, in Pancreatic Cancer 86 (Douglas B. Evans et al. eds., 2002); Ishiguchi, T. et al., Hepatogastroenterology 48(40): 923-27 (2001), despite the fact that it frequently underestimates the extent of the cancer, as small-volume metastases are often beyond the resolution of CT, H. J. Kim & K. C. Conlon, Laparascopic Staging, in Pancreatic Cancer 15 (Douglas B. Evans et al. eds., 2002). MRI may at some point supplant CT in view of, inter alia, its ability to (1) contrast among various tissue, (2) modify pulse sequences to improve visualization of lesions and minimize artifacts, (3) perform imaging while limiting a patient's exposure to ionizing radiation, and (4) visualize vessels without using IV iodinated contrast reagents. Kaur et al., supra at 87. At present, however, MRI has not demonstrated a clear advantage over CT. Kim & Conlon, supra at 116.
A variety of ultrasonic techniques are also currently employed in staging, including transabdominal ultrasound (TUS), endoscopic ultrasound (EUS), and intraoperative ultrasound (JUS), with EUS being one of the most promising. Kaur et al., supra at 86; Richard A. Erickson, Endoscopic Diagnosis and Staging: Endoscopic Ultrasound, Endoscopic Retrograde Cholangiopancreatography, in Pancreatic Cancer 97-106 (Douglas B. Evans et al. eds., 2002). These techniques, however, are each limited by a variety of factors: TUS is hindered by gas in the gastrointestinal tract and fat in the peritoneum, EUS requires considerable experience in ultrasonography and endoscopy and may not be widely available, and IUS can only be used intraoperatively. Kaur et al., supra at 86.
Although in its nascent stages, the search for markers that will assist in staging pancreatic cancer has found some possible leads. For example, research has revealed that two metastasis-suppressing genes, nm23-H1 and KAI1, are differentially expressed depending on the stage of pancreatic cancer, with their expression being upregulated at early stages and down regulated at later stages of the disease. Friess, H. et al., J. Clin. Oncol. 19(9): 2422-32 (2001). Researchers have also focused on genetic lymph node staging, particularly searching for mutations in the K-ras proto-oncogene. Yamada, T. et al., Int'l J. Oncol. 16(6): 1165-71 (2000). Likewise, research has identified that the presence of mutated K-ras sequences in plasma/serum is associated with late stage pancreatic cancer, although the presence of early stage pancreatic cancer can be detected this way as well. Sorenson, G. D., Clin. Cancer Res. 6(6): 2129-37 (2000). A promising staging technique using a multimarker reverse transcriptase-polymerase chain reaction assay has successfully distinguished pancreatic cancer stages by assaying blood and tissue samples for mRNA expression of the following tumor markers: the β-human chorionic gonadotropin gene, the hepatocyte growth factor receptor gene c-met, and the β-1,4-N-acetyl-galactosaminyl-transferase gene. Bilchik, A. et al., Cancer 88(5): 1037-44 (2000).
One classification system commonly used to stage pancreatic cancer is the TNM system devised by the Union Internationale Contre le Cancer. AJCC Cancer Staging Handbook 3 (Irvin D. Fleming et al. eds., 5th ed. 1998). This system is divided into several stages, each of which evaluates the extent of cancer growth with respect to primary tumor (T), regional lymph nodes (N), and distant metastasis (M). Id.
Stage 0 is characterized by carcinoma in situ (Tis), with no regional lymph node metastasis (N0) and no distant metastasis (M0). Id. at 113. Stages I and II differ from stage 0 only in terms of tumor category: stage I involves a tumor limited only to the pancreas that is either (1) 2 cm or less in greatest dimension (T1) or (2) more than 2 cm in greatest dimension (T2), while stage II involves a tumor that extends directly into the duodenum, bile duct, or peripancreatic tissues (T3). Id. Stage III involves tumor category T1, T2, or T3; regional lymph node metastasis (N1), which involves either a single lymph node (pN1a) or multiple lymph nodes (pN1b); and no distant metastasis (M0). Stage IVA is characterized by tumor extension directly into the stomach, spleen, colon, or adjacent large vessels (T4); any N category; and no distant metastasis (M0). Lastly, stage IVB is characterized by any T category, any N category, and distant metastasis (M1). Id.
Once the cancer has been staged, the only consistently effective treatment for the disease is surgery, and with only ten to fifteen percent of patients being able to undergo potentially curative resection. Jean et al., supra at 15; Fleming et al. eds., supra at 111; William F. Regine, Postoperative Adjuvant Therapy: Past, Present, and Future Trial Development, in Pancreatic Cancer 235 (Douglas B. Evans et al. eds., 2002). Moreover, the five-year survival of those patients undergoing resection is below twenty percent. Regine, supra at 235. While chemotherapeutic agents such as gemcitabine and 5-fluorouracil have shown some effectiveness against pancreatic carcinomas, the reality is that chemotherapy has shown little impact on survival from pancreatic cancer. Burdette, supra at 101. Radiation therapy has provided conflicting results with respect to its efficacy, id., although radiation in combination with 5-fluorouracil has shown some promise, Regine, supra at 235.
In view of the failure of conventional techniques at treating pancreatic cancer, a number of novel approaches employing the techniques of molecular biology have been investigated. Considerable research has been performed in the area of gene therapy, including antisense technology, gene-directed prodrug activation strategies, promoter gene strategies, and oncolytic viral therapies. Eugene A. Choi & Francis R. Spitz, Strategies for Gene Therapy, in Pancreatic Cancer 331 (Douglas B. Evans et al. eds., 2002); Kasuya, H. et al., Hepatogastroenterology 48(40): 957-61 (2001). Other recent approaches have focused on the inhibition of matrix metalloproteinases, enzymes which facilitate the metastasis and invasion of tumor cells through their degradation of basement membranes, and their role in peritumoral stromal degradation and angiogenesis. Alexander S. Rosemurgy, II & Mahmudul Haq, Role of Matrix Metalloproteinase Inhibition in the Treatment of Pancreatic Cancer, in Pancreatic Cancer 369 (Douglas B. Evans et al. eds., 2002).
From the foregoing, it is clear that procedures used for detecting, diagnosing, monitoring, staging, prognosticating, and preventing the recurrence of pancreatic cancer are of critical importance to the outcome of the patient. Moreover, current procedures, while helpful in each of these analyses, are limited by their specificity, sensitivity, invasiveness, and/or their cost. As such, highly specific and sensitive procedures that would operate by way of detecting novel markers in cells, tissues, or bodily fluids, with minimal invasiveness and at a reasonable cost, would be highly desirable.
Lung Cancer
Throughout the last hundred years, the incidence of lung cancer has steadily increased, so much so that now in many countries, it is the most common cancer. In fact, lung cancer is the second most prevalent type of cancer for both men and women in the United States and is the most common cause of cancer death in both sexes. Lung cancer deaths have increased ten-fold in both men and women since 1930, primarily due to an increase in cigarette smoking, but also due to an increased exposure to arsenic, asbestos, chromates, chloromethyl ethers, nickel, polycyclic aromatic hydrocarbons and other agents. See Scott, Lung Cancer: A Guide to Diagnosis and Treatment, Addicus Books (2000) and Alberg et al., in Kane et al. (eds.) Biology of Lung Cancer, pp. 11-52, Marcel Dekker, Inc. (1998). The American Cancer Society estimates there will be over 173,550 new cases of lung cancer in 2004. Additionally, there will be an estimated 160,440 deaths from lung cancer in 2004. ACS Website: cancer with the extension .org of the world wide web.
Lung cancer may result from a primary tumor originating in the lung or a secondary tumor which has spread from another organ such as the bowel or breast. Although there are over a dozen types of lung cancer, over 90% fall into two categories: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). See Scott, supra. About 20-25% of all lung cancers are characterized as SCLC, while 70-80% are diagnosed as NSCLC. Id. A rare type of lung cancer is mesothelioma, which is generally caused by exposure to asbestos, and which affects the pleura of the lung. Lung cancer is usually diagnosed or screened for by chest x-ray, CAT scans, PET scans, or by sputum cytology. A diagnosis of lung cancer is usually confirmed by biopsy of the tissue. Id.
SCLC tumors are highly metastatic and grow quickly. By the time a patient has been diagnosed with SCLC, the cancer has usually already spread to other parts of the body, including lymph nodes, adrenals, liver, bone, brain and bone marrow. See Scott, supra; Van Houtte et al. (eds.), Progress and Perspective in the Treatment of Lung Cancer, Springer-Verlag (1999). Because the disease has usually spread to such an extent that surgery is not an option, the current treatment of choice is chemotherapy plus chest irradiation. See Van Houtte, supra. The stage of disease is a principal predictor of long-term survival. Less than 5% of patients with extensive disease that has spread beyond one lung and surrounding lymph nodes, live longer than two years. Id. However, the probability of five-year survival is three to four times higher if the disease is diagnosed and treated when it is still in a limited stage, i.e., not having spread beyond one lung. Id.
NSCLC is generally divided into three types: squamous cell carcinoma, adenocarcinoma and large cell carcinoma. Both squamous cell cancer and adenocarcinoma develop from the cells that line the airways; however, adenocarcinoma develops from the goblet cells that produce mucus. Large cell lung cancer has been thus named because the cells look large and rounded when viewed microscopically, and generally are considered relatively undifferentiated. See Yesner, Atlas of Lung Cancer, Lippincott-Raven (1998).
Secondary lung cancer is a cancer initiated elsewhere in the body that has spread to the lungs. Cancers that metastasize to the lung include, but are not limited to, breast cancer, melanoma, colon cancer and Hodgkin's lymphoma. Treatment for secondary lung cancer may depend upon the source of the original cancer. In other words, a lung cancer that originated from breast cancer may be more responsive to breast cancer treatments and a lung cancer that originated from the colon cancer may be more responsive to colon cancer treatments.
The stage of a cancer indicates how far it has spread and is an important indicator of the prognosis. In addition, staging is important because treatment is often decided according to the stage of a cancer. SCLC is divided into two stages: limited disease, i.e., cancer that can only be seen in one lung and in nearby lymph nodes; and extensive disease, i.e., cancer that has spread outside the lung to the chest or to other parts of the body. For most patients with SCLC, the disease has already progressed to lymph nodes or elsewhere in the body at the time of diagnosis. See Scott, supra. Even if spreading is not apparent on the scans, it is likely that some cancer cells may have spread away and traveled through the bloodstream or lymph system. In general, chemotherapy with or without radiotherapy is often the preferred treatment. The initial scans and tests done at first will be used later to see how well a patient is responding to treatment.
In contrast, non-small cell cancer may be divided into four stages. Stage I is highly localized cancer with no cancer in the lymph nodes. Stage II cancer has spread to the lymph nodes at the top of the affected lung. Stage III cancer has spread near to where the cancer started. This can be to the chest wall, the covering of the lung (pleura), the middle of the chest (mediastinum) or other lymph nodes. Stage IV cancer has spread to another part of the body. Stage I-III cancer is usually treated with surgery, with or without chemotherapy. Stage IV cancer is usually treated with chemotherapy and/or palliative care.
A number of chromosomal and genetic abnormalities have been observed in lung cancer. In NSCLC, chromosomal aberrations have been described on 3p, 9p, 11p, 15p and 17p, and chromosomal deletions have been seen on chromosomes 7, 11, 13 and 19. See Skarin (ed.), Multimodality Treatment of Lung Cancer, Marcel Dekker, Inc. (2000); Gemmill et al., pp. 465-502, in Kane, supra; Bailey-Wilson et al., pp. 53-98, in Kane, supra. Chromosomal abnormalities have been described on 1p, 3p, 5q, 6q, 8q, 13q and 17p in SCLC. Id. In addition, the loss of the short arm of chromosome 3p has also been seen in greater than 90% of SCLC tumors and approximately 50% of NSCLC tumors. Id.
A number of oncogenes and tumor suppressor genes have been implicated in lung cancer. See Mabry, pp. 391-412, in Kane, supra and Sclafani et al., pp. 295-316, in Kane, supra. In both SCLC and NSCLC, the p53 tumor suppressor gene is mutated in over 50% of lung cancers. See Yesner, supra. Another tumor suppressor gene, FHIT, which is found on chromosome 3p, is mutated by tobacco smoke. Id.; Skarin, supra. In addition, more than 95% of SCLCs and approximately 20-60% of NSCLCs have an absent or abnormal retinoblastoma (Rb) protein, another tumor suppressor gene. The ras oncogene (particularly K-ras) is mutated in 20-30% of NSCLC specimens and the c-erbB2 oncogene is expressed in 18% of stage 2 NSCLC and 60% of stage 4 NSCLC specimens. See Van Houtte, supra. Other tumor suppressor genes that are found in a region of chromosome 9, specifically in the region of 9p21, are deleted in many cancer cells, including p16INK4A and p15INK4B. See Bailey-Wilson, supra; Sclafani et al., supra. These tumor suppressor genes may also be implicated in lung cancer pathogenesis.
In addition, many lung cancer cells produce growth factors that may act in an autocrine or paracrine fashion on lung cancer cells. See Siegfried et al., pp. 317-336, in Kane, supra; Moody, pp. 337-370, in Kane, supra and Heasley et al., 371-390, in Kane, supra. In SCLC, many tumor cells produce gastrin-releasing peptide (GRP), which is a proliferative growth factor for these cells. See Skarin, supra. Many NSCLC tumors express epidermal growth factor (EGF) receptors, allowing NSCLC cells to proliferate in response to EGF. Insulin-like growth factor (IGF-I) is elevated in greater than 95% of SCLC and greater than 80% of NSCLC tumors; it is thought to function as an autocrine growth factor. Id. Finally, stem cell factor (SCF, also known as steel factor or kit ligand) and c-Kit (a proto-oncoprotein tyrosine kinase receptor for SCF) are both expressed at high levels in SCLC, and thus may form an autocrine loop that increases proliferation. Id.
Although the majority of lung cancer cases are attributable to cigarette smoking, most smokers do not develop lung cancer. Epidemiological evidence has suggested that susceptibility to lung cancer may be inherited in a Mendelian fashion, and thus have an inherited genetic component. Bailey-Wilson, supra. Thus, it is thought that certain allelic variants at some genetic loci may affect susceptibility to lung cancer. Id. One way to identify which allelic variants are likely to be involved in lung cancer susceptibility, as well as susceptibility to other diseases, is to look at allelic variants of genes that are highly expressed in lung.
The lung is susceptible to a number of other debilitating diseases as well, including, without limitation, emphysema, pneumonia, cystic fibrosis and asthma. See Stockley (ed.), Molecular Biology of the Lung, Volume I: Emphysema and Infection, Birkhauser Verlag (1999), hereafter Stockley I, and Stockley (ed.), Molecular Biology of the Lung, Volume II: Asthma and Cancer, Birkhauser Verlag (1999), hereafter Stockley II. The cause of many these disorders is still not well understood and there are few, if any, good treatment options for many of these noncancerous lung disorders. Thus, there remains a need to understand various noncancerous lung disorders and to identify treatments for these diseases.
The development and differentiation of lung tissue during embryonic development is also very important. All of the epithelial cells of the respiratory tract, including those of the lung and bronchi, are derived from the primitive endodermal cells that line the embryonic outpouching. See Yesner, supra. During embryonic development, multipotent endodermal stem cells differentiate into many different types of specialized cells, which include ciliated cells for moving inhaled particles, goblet cells for producing mucus, Kulchitsky's cells for endocrine function, and Clara cells and type II pneumocytes for secreting surfactant protein. Id. Improper development and differentiation may cause respiratory disorders and distress in infants, particularly in premature infants, whose lungs cannot produce sufficient surfactant when they are born. Further, some lung cancer cells, particularly small cell carcinomas, are plastic and can alter their phenotype into a number of cell types, including large cell carcinoma, adenocarcinoma and squamous cell carcinoma. Id. Thus, a better understanding of lung development and differentiation may help facilitate understanding of lung cancer initiation and progression.
The most common screening tests for lung cancer are chest x-ray and sputum cytology. Randomized controlled trials have not demonstrated a reduction in lung cancer mortality resulting from screening with chest x-ray and/or sputum cytology. Additionally, sputum cytology has not been shown to be effective when used as an adjunct to annual chest x-ray. Screening with chest x-ray plus sputum cytology appears to detect lung cancer at an earlier stage, but this would be expected in a screening test whether or not it was effective at reducing mortality. Since early detection by current screening methods fails to reduce mortality in lung cancer patients, current lung cancer screening methods are inadequate.
There are two important potential hazards associated with chest radiography screening. First, false positive test results can lead to an unnecessary invasive procedure, such as percutaneous needle biopsy or thoracotomy. These procedures are costly and due to their invasive nature carry risks of their own. The second hazard with chest radiography screening is overdiagnosis. Overdiagnosis is the diagnosis of a small or slowly growing tumor that would not have become clinically significant had it not been detected by screening. Although overdiagnosis is almost impossible to document in a living individual, autopsy studies suggest that many individuals die with lung cancer rather than from it.
Additionally, the spectrum of lung cancer type has shifted over the last two decades. Whereas the most common type used to be squamous cell cancer (usually centrally located), the most common type now is adenocarcinoma (usually peripherally located). The latter may be more amenable to early detection by chest x-ray, the limitations of which are described above. In contrast, sputum cytology, is more sensitive in the detection of squamous cell cancer than in detecting adenocarcinoma, and therefore lacks usefulness in detecting the more common adenocarcinomas. Clearly, new highly sensitive non-invasive methods of detecting lung cancer are needed.
There are intensive efforts to improve lung cancer screening with newer technologies, including low-dose helical computed tomography (LDCT) and molecular techniques. LDCT is far more sensitive than chest radiography. In a recent screening study, CT detected almost 6 times as many stage I lung cancers as chest radiography and most of these tumors were 1 cm or less in diameter. However, the effectiveness of screening with LDCT has not yet been evaluated in a controlled clinical trial.
There are two potential hazards that must be considered against any potential benefit of screening with LDCT. The more common and familiar hazard is the false positive test result, which may lead to anxiety and invasive diagnostic procedures. A less familiar hazard is overdiagnosis, the diagnosis of a condition that would not have become clinically significant had it not been detected by screening. In the case of screening with LDCT, overdiagnosis could lead to unnecessary diagnosis of lung cancer requiring some combination of surgery, e.g., lobectomy, chemotherapy and radiation therapy. As stated above, overdiagnosis is almost impossible to document in a living individual. In one large study, about one-sixth of all lung cancers found at autopsy had not been clinically recognized before death. Furthermore, autopsy probably fails to detect many small lung cancers that are detectable by CT.
Current therapies for lung cancer are quite limited. Generally, patient options comprise surgery, radiation therapy, and chemotherapy.
Depending on the type and stage of a lung cancer, surgery may be used to remove the tumor along with some surrounding lung tissue. A lobectomy refers to a lobe (section) of the lung being removed. If the entire lung is removed, the surgery is called a pneumonectomy. Removing only part of a lobe is known as a segmentectomy or wedge resection.
If the cancer has spread to the brain, benefit may be gained from removal of the brain metastasis. This involves a craniotomy (surgery through a hole in the skull).
For radiation therapy several methods exist. External beam radiation therapy uses radiation delivered from outside the body that is focused on the cancer. This type of radiation therapy is most often used to treat a primary lung cancer or its metastases to other organs.
Brachytherapy uses a small pellet of radioactive material placed directly into the cancerous tissue or into the airway next to the cancer. Radiation therapy is sometimes used as the main (primary) treatment of lung cancer, especially if the general health of the patient is too poor to undergo surgery. Brachytherapy can also be used to help relieve blockage of large airways by cancer.
Additionally, radiation therapy can be used as a post surgical treatment to kill very small deposits of cancer that cannot be seen or removed during surgery. Radiation therapy can also be used to palliate (relieve) symptoms of lung cancer such as pain, bleeding, difficulty swallowing, and problems caused by brain metastases.
For chemotherapy, cisplatin or a related drug, carboplatin, are the chemotherapy agents most often used in treating NSCLC. Recent studies found that combining either of these with drugs such as gemcitabine, paclitaxel, docetaxel, etoposide, or vinorelbine appear to be more effective in treating NSCLC.
Recently, the National Comprehensive Cancer Network (NCCN; nccn with the extension .org of the world wide web), an alliance of nineteen of the world's leading cancer centers, announces a major update of the NCCN Non-Small Cell Lung Cancer Clinical Practice Guidelines. The NCCN is widely recognized as a standard for clinical policy in oncology.
Recently approved targeted therapy, gefitinib (IRESSA®, AstraZeneca Pharmaceuticals LP) is now recommended as third-line therapy and as second-line only if the platinum/docetaxel combination was used as first-line therapy.
The NCCN's Non-Small Cell Lung Cancer (NSCLC) guidelines contain recommendations for administration of chemotherapy to patients with this disease including patient selection criteria and definition of first-, second-, and third-line agents and combinations.
Chemotherapeutic agents are specified as two-agent regimens for first-line therapy, two agent regimens or single agents for second-line therapy, and one single agent for third-line therapy. Agents used in first- and second-line therapy are: cisplatin (PLATINOL®, Bristol-Myers Squibb Company), carboplatin (PARAPLATIN®, Bristol-Myers Squibb Company), paclitaxel (TAXOL®, Bristol-Myers Squibb Company), docetaxel (TAXOTERE®, Aventis Pharmaceuticals Inc.), vinorelbine (NAVELBINE®, GlaxoSmithKline), gemcitabine (GEMZAR®, Eli Lilly and Company), etoposide (TOPOSAR®, Pfizer, Inc.; VEPESID®, Bristol-Myers Squibb Company; ETOPOPHOS®, Bristol-Myers Squibb Company), irinotecan (CAMPTOSAR®, Pfizer, Inc.), vinblastine (VELBAN®, Eli Lilly and Company), mitomycin (MUTAMYCIN®, Bristol-Myers Squibb Company), and ifosfamide (IFEX®, Bristol-Myers Squibb Company).
Some of the usual chemotherapy combinations used for patients with SCLC include: EP (etoposide and cisplatin); ET (etoposide and carboplatin); ICE (ifosfamide, carboplatin, and etoposide); and CAV (cyclophosphamide, doxorubicin, and vincristine).
New drugs such as gemcitabine, paclitaxel, vinorelbine, topotecan, and teniposide have shown promising results in some SCLC studies. Growth factors may be given in conjunction to chemotherapy agents if patient health is good. The administration of growth factors help prevent bone marrow side effects.
Ongoing or recently completed therapeutic trials for various compounds to treat lung cancer include alitretinoin (PANRETIN®, Ligand Pharmaceuticals), topotecan HCl (HYCAMTIN®, GlaxoSmithKline), liposomal ether lipid (Elan Pharmaceutical), cantuzumab mertansine (ImmunoGen), oncolytic virus therapy (GAVAX®, Cell Genesys), vincristine (ONCO TCS®, Inex Pharmaceuticals), a concentrate of shark cartilage (NEOVASTAT®, AEterna Laboratories), squalamine (Genaera), mirostipen (Human Genome Sciences Inc.), p53 tumor suppressor therapy (ADVEXINN®, Introgen Therapeutics), biricodar dicitrate (INCEL®, Vertex Pharmaceuticals), flavopiridol (Aventis), pemetrexed (ALIMTA®, Eli Lilly and Company), pivaloyloxymethylbutyrate (PIVANEX®, Titan Pharmaceuticals), tirapazamine (TIRAZONE®, Sanofi-Synthelabo Pharmaceuticals), irinotecan (CAMPTOSAR®, Pharmacia), tezacitabine (Chiron), cisplatin/vinblastine/amifostine (MedImmune), paclitaxel/carboplatin/amifostine (MedImmune), antisense agent (ONCOMYC-NG®, AVI BioPharma), exisulind/vinorelbine (APTOSYN®/NAVELBINE®, Cell Pathyways), tariquidar (QLT), paclitaxel poliglumex (XYOTAX®, Cell Therapeutics), PEG-camptothecin (PROTHECAN®, Enzon), decitabine (SuperGen), erlotinib (TARCEVA®, OSI Pharmaceuticals), ABX-EGF (Abgenix), vitamin E-based emulsion formulation of paclitaxel (TOCOSOL PACLITAXEL®, Sonus Pharmaceuticals), a fragment of the mouse antibody HMFG-1 labeled with yttrium 90 (THERAFAB®, Antisoma), minodronate (Yamanouchi Pharmaceutical), exisulind/docetaxel/carboplatin (APTOSYN®/TAXOTERE®V/PARAPLATIN®, Cell Pathways), exisulind/gemcitabine HCl (APTOSYN®/GEMZAR®), Cell Pathways), IMC-C225/carboplatin/paclitaxel (ERBITUX®/CARBOPLATIN®/PACLITAXEL®, ImClone Systems), and vinorelbine (NAVELBINE®, GlaxoSmithKline).
As indicated above, many therapeutics are recommended for use in combination as a first-line therapy or only if other therapeutics have failed as second-, and third-line agents. While there are many compounds in ongoing or recently completed therapeutic trials, there is great need for additional therapeutic compounds capable of treating early stage and advanced or metastasized lung cancer.
Accordingly, there is a great need for more sensitive and accurate methods for predicting whether a person is likely to develop lung cancer, for diagnosing lung cancer, for monitoring the progression of the disease, for staging the lung cancer, for determining whether the lung cancer has metastasized and for imaging the lung cancer. There is also a need for better treatment of lung cancer. Further, there is a great need for diagnosing and treating noncancerous lung disorders such as emphysema, pneumonia, lung infection, pulmonary fibrosis, cystic fibrosis and asthma. There is also a need for compositions and methods of using these compositions to identify lung tissue for forensic purposes and for determining whether a particular cell or tissue exhibits lung-specific characteristics.
As discussed above, each of the methods for diagnosing and staging breast, ovarian pancreatic, and lung cancer is limited by the technology employed. Accordingly, there is need for sensitive molecular and cellular markers and reagents for the detection of breast, ovarian, pancreatic and lung cancer including metastatic cancer. There is a need for molecular markers and reagents for the accurate staging, including clinical and pathological staging, of breast, ovarian, pancreatic and lung cancers to optimize treatment methods. Finally, there is a need for sensitive molecular and cellular markers and reagents to monitor the progress of cancer treatments, including markers that can detect recurrence of breast, ovarian, pancreatic and lung cancers following remission.
The present invention provides alternative reagents and methods for treating breast, ovarian, pancreatic and lung cancer that overcome the limitations of conventional therapeutic methods as well as offer additional advantages that will be apparent from the detailed description below.
Angiogenesis in Cancer
Growth and metastasis of solid tumors are also dependent on angiogenesis. Folkman, J., 1986, Cancer Research, 46, 467-473; Folkman, J., 1989, Journal of the National Cancer Institute, 82, 4-6. It has been shown, for example, that tumors which enlarge to greater than 2 mm must obtain their own blood supply and do so by inducing the growth of new capillary blood vessels. Once these new blood vessels become embedded in the tumor, they provide a means for tumor cells to enter the circulation and metastasize to distant sites such as liver, lung or bone. Weidner, N., et al., 1991, The New England Journal of Medicine, 324(1), 1-8.
Angiogenesis, defined as the growth or sprouting of new blood vessels from existing vessels, is a complex process that primarily occurs during embryonic development. The process is distinct from vasculogenesis, in that the new endothelial cells lining the vessel arise from proliferation of existing cells, rather than differentiating from stem cells. The process is invasive and dependent upon proteolysis of the extracellular matrix (ECM), migration of new endothelial cells, and synthesis of new matrix components. Angiogenesis occurs during embryogenic development of the circulatory system; however, in adult humans, angiogenesis only occurs as a response to a pathological condition (except during the reproductive cycle in women).
Under normal physiological conditions in adults, angiogenesis takes place only in very restricted situations such as hair growth and wounding healing. Auerbach, W. and Auerbach, R., 1994, Pharmacol Ther. 63(3):265-3 11; Ribatti et al., 1991, Haematologica 76(4):3 11-20; Risau, 1997, Nature 386(6626):67 1-4. Angiogenesis progresses by a stimulus which results in the formation of a migrating column of endothelial cells. Proteolytic activity is focused at the advancing tip of this “vascular sprout”, which breaks down the ECM sufficiently to permit the column of cells to infiltrate and migrate. Behind the advancing front, the endothelial cells differentiate and begin to adhere to each other, thus forming a new basement membrane. The cells then cease proliferation and finally define a lumen for the new arteriole or capillary.
Unregulated angiogenesis has gradually been recognized to be responsible for a wide range of disorders, including, but not limited to, cancer, cardiovascular disease, rheumatoid arthritis, psoriasis and diabetic retinopathy. Folkman, 1995, Nat Med 1(1):27-31; Isner, 1999, Circulation 99(13): 1653-5; Koch, 1998, Arthritis Rheum 41(6):951-62; Walsh, 1999, Rheumatology (Oxford) 38(2):103-12; Ware and Simons, 1997, Nat Med 3(2): 158-64.
Of particular interest is the observation that angiogenesis is required by solid tumors for their growth and metastases. Folkman, 1986 supra; Folkman 1990, J Natl. Cancer Inst., 82(1) 4-6; Folkman, 1992, Semin Cancer Biol 3(2):65-71; Zetter, 1998, Annu Rev Med 49:407-24. A tumor usually begins as a single aberrant cell which can proliferate only to a size of a few cubic millimeters due to the distance from available capillary beds, and it can stay ‘dormant’ without further growth and dissemination for a long period of time. Some tumor cells then switch to the angiogenic phenotype to activate endothelial cells, which proliferate and mature into new capillary blood vessels. These newly formed blood vessels not only allow for continued growth of the primary tumor, but also for the dissemination and recolonization of metastatic tumor cells. The precise mechanisms that control the angiogenic switch is not well understood, but it is believed that neovascularization of tumor mass results from the net balance of a multitude of angiogenesis stimulators and inhibitors Folkman, 1995, supra.
One of the most potent angiogenesis inhibitors is endostatin identified by O'Reilly and Folkman. O'Reilly et al., 1997, Cell 88(2):277-85; O'Reilly et al., 1994, Cell 79(2):3 15-28. Its discovery was based on the phenomenon that certain primary tumors can inhibit the growth of distant metastases. O'Reilly and Folkman hypothesized that a primary tumor initiates angiogenesis by generating angiogenic stimulators in excess of inhibitors. However, angiogenic inhibitors, by virtue of their longer half-life in the circulation, reach the site of a secondary tumor in excess of the stimulators. The net result is the growth of primary tumor and inhibition of secondary tumor. Endostatin is one of a growing list of such angiogenesis inhibitors produced by primary tumors. It is a proteolytic fragment of a larger protein: endostatin is a 20 kDa fragment of collagen XVIII (amino acid H1132-K1315 in murine collagen XVIII). Endostatin has been shown to specifically inhibit endothelial cell proliferation in vitro and block angiogenesis in vivo. More importantly, administration of endostatin to tumor-bearing mice leads to significant tumor regression, and no toxicity or drug resistance has been observed even after multiple treatment cycles. Boehm et al., 1997, Nature 390(6658):404-407. The fact that endostatin targets genetically stable endothelial cells and inhibits a variety of solid tumors makes it a very attractive candidate for anticancer therapy. Fidler and Ellis, 1994, Cell 79(2): 185-8; Gastl et al., 1997, Oncology 54(3):177-84; Hinsbergh et al., 1999, Ann Oncol 10 Suppl 4:60-3. In addition, angiogenesis inhibitors have been shown to be more effective when combined with radiation and chemotherapeutic agents. Klement, 2000, J. Clin Invest, 105(8) R15-24. Browder, 2000, Cancer Res. 6-(7) 1878-86, Arap et al., 1998, Science 279(5349):377-80; Mauceri et al., 1998, Nature 394(6690):287-91.
The present invention provides alternative methods of treating breast, ovarian, pancreatic and lung cancer that overcome the limitations of conventional therapeutic methods as well as offer additional advantages that will be apparent from the detailed description below.